Method of stretching single-stranded nucleic acid, single-stranded nucleic acid stretching system and dna chip

Abstract

To verify an action of a high-frequency ac electric field on a single-stranded nucleic acid existing in an aqueous solution. This action is used to improve the efficiency of hybridization to which the single-stranded nucleic acid is subjected as a complementary strand. Provided are a method and system for stretching a single-stranded nucleic acid, which exists in a free form in pure water or an aqueous solution (R) of pH 5 to 11, or which exists in a form immobilized on one of surface (f) of an electrode (E) of opposing electrodes (E,E) arranged facing the aqueous solution (R) or in a form immobilized on surfaces (f) of both electrodes (E) of opposing electrodes (E, E), by causing a high-frequency ac electric field to act on the single-stranded nucleic acid.

1 . A nucleic acid stretch method of stretching the following single-stranded nucleic acid ( 1 ) or ( 2 ) by causing an ac electric field of a high frequency to act on said single-stranded nucleic acid ( 1 ) or ( 2 ): 
 (1) a single-stranded nucleic acid existing in a free form in pure water or an aqueous solution of pH 5 to 11, or    (2) a single-stranded nucleic acid existing in a form immobilized on one or both of opposing electrodes arranged facing said aqueous solution.    
   
   
       2 . The nucleic acid stretch method according to  claim 1 , wherein said high frequency has a frequency of 500 kHz or higher, and a voltage is applied to give an electric field strength of 1.2 V/μm or higher.  
   
   
       3 . The nucleic acid stretch method according to  claim 1 , wherein a distance between said opposing electrodes is set at 40 μm or shorter.  
   
   
       4 . The nucleic acid stretch method according to  claim 1 , wherein said stretch of said single-stranded nucleic acid is effected by dielectrophoresis.  
   
   
       5 . A nucleic acid stretch system, characterized in that hybridization is conducted by using, as one of complementary strands, a single-stranded nucleic acid stretched by a method according to  claim 1 .  
   
   
       6 . A nucleic acid stretch system provided at least with a reaction well capable of storing an aqueous solution therein and a means for forming a high-frequency ac electric field in said reaction well, characterized in that a single-stranded nucleic acid existing in said reaction well is stretched under an action of said high-frequency ac electric field.  
   
   
       7 . The nucleic acid stretch system according to  claim 6 , wherein said reaction well is provided with at least a pair of opposing electrode, and said single-stranded nucleic acid is immobilized at an end thereof on a surface or surfaces of one or both of said opposing electrodes.  
   
   
       8 . The nucleic acid stretch system according to  claim 7 , wherein a distance between said opposing electrodes is 40 μm or shorter.  
   
   
       9 . A nucleic acid stretch system, characterized in that using an stretched single-stranded nucleic acid as one of complementary strands, hybridization is conducted in said reaction well as described in  claim 6 .  
   
   
       10 . A DNA chip characterized by use of a means for stretching a single-stranded nucleic acid, which exists in a free or immobilized form in an aqueous solution of pH 5 to 11, under an action of a high-frequency ac electric field applied to a reaction well with pure water or said aqueous solution retained therein.